A. that you have observed B. that how you have observed C. how that you have observed D. how what you have observed 参考答案:D 答案解析:名词性从句。从空格处开始为宾语从句,同时这个宾语从句中还包含一个主语从句。
第26题: [单项选择]I have always ______ Mary ______ one of my best friends. A. regard ... as B. regard ... for C. regarded ... as D. regarded... for 参考答案:C 答案解析:短语regard...as意为“把……视为”,B和D错误,前面有have要和一个过去分词一起构成完成时,A用动词原形不对,C正确。